The Vermis
The vermis, or cerebellar vermis, actually looks like what he is named after: vermis is Latin for “worm”. But this special worm has a tongue, an uvula, and a summit, and it helps us stay steady when we're standing and walking. It keeps us from stumbling around like we're drunk.
Scientific support: Dr. Björn Spittau
Published: 01.10.2025
Difficulty: intermediate
The vermis is the worm-like central section of the cerebellum. It controls our balance and keeps us from stumbling when we walk.
The worm in the brain – it's not a pleasant association that comes to mind with this cerebellar structure. But the vermis does indeed resemble a worm wriggling between the hemispheres of the cerebellum. This is also due to the transverse grooves in the cerebellar cortex, which divide it into dozens of segments. However, the vermis has nothing to do with the typical crawling of a worm: it primarily coordinates the motor skills involved in walking and standing.
If the hemispheres were described as bulging butterfly wings, the worm would correspond to the insect's body in between. It wraps around the hemispheres and is only interrupted at the front, towards the brain stem, by the cerebellar peduncles and the fourth ventricle. Ancient anatomists gave some sections along the vermis very vivid, sometimes poetic names. The vermis has a summit (culmen), a slope (declive), a pyramid (pyramis) and – even more unusual for a worm – a tongue (lingula), a tubercle (tuber), an uvula and a nodule (nodulus). To help medical students remember the sequence of these sections, someone created this sentence: “Like Cats Catching Dogs For The Party Up North.” You guessed it: the first letters of the words represent the first letters of the individual sections of the worm. But as beautiful as the names are, they have little functional significance.
The largest part of the vermis, together with the directly adjacent hemispheric areas –the so-called paravermal zone – forms the paleocerebellum, the old cerebellum. Since its inputs originate mainly from the spinal cord, it is also called the spinocerebellum. The nodulus, the lowest segment of the vermis, is considered part of the flocculonodular lobe, while the declive is considered part of the neocerebellum.
The functions of the cerebellar vermis
While the nodulus, as part of the flocculonodular lobe, primarily serves to regulate balance and the declive, together with the cerebellar hemispheres, is involved in voluntary movements – such as scratching your head – the spinocerebellum processes proprioceptive signals, i.e., those relating to muscle tone and body position. In this way, it is always informed about the position of the body in space and ensures the smooth functioning of walking and standing through its descending signals. What sounds quite simple has complex components: the interaction of antagonistic muscle groups, for example, or those that counteract gravity. The control of inertia or centrifugal forces is also part of this. If the vermis is damaged, however, this typically results in a swaying, staggering gait, as seen in a drunk person.
The core inside
Hidden in the medulla of the vermis is a paired nucleus, the nucleus fastigii – in English, the roof ridge or gable nucleus. It is one of four cerebellar nuclei and the only one that is attributed to the vermis. The name comes from its location in the roof of the fourth ventricle. After switching in the nucleus fastigii, fibers from the vermis leave the cerebellum and travel to the vestibular nuclei and the reticular formation.
First published on August 28, 2011
Last updated on October 1, 2025
